Heroes was never all that great, imo. Even from the pilot, the acting and dialogue were pretty terrible to me. It had one great episode written by the brilliant Bryan Fuller...who then left to create a far superior show (here's where I weep yet again for Pushing Daisies). That said, I hope the effects in SHIELD are more on par with that show and less with Once Upon a Time, because the CGI in Once is my absolute least favorite part about it. The FX seemed to improve a bit in S2, but in S1, they were sometimes downright atrocious.

Of course, SHIELD should be a little less dependent on green screen, so that should help.